Report of the Movement Disorders Sections from the 51st Annual American Academy of Neurology Meeting
Conference CoverageNeurology Alert reviews approximately 20 of the most important and clinically relevant presentations from the 51st Annual American Academy of Neurology meeting. The poster or seminar numbers for each presentation are listed with the abstracts in the April 1999 supplement to Neurology.
Molecular genetics continue to improve our understanding of inherited movement disorders. Two families were reported (S05.005) with rapid-onset Dystonia-Parkinsonism linked to chromosome 19. An autosomal dominant disorder, it is characterized by the development of dystonia, parkinsonism, and dysarthria over hours to days. A new autosomal dominant spinocerebellar ataxia (SCA 10) was linked to a region of chromosome 22 (S33.006). Like other SCAs with known genetic loci (SCA 1, 2, 3, 6, and 7), patients with SCA10 have inheritance, predominantly cerebellar symptoms, and evidence of anticipation. They also frequently have epilepsy, a clinical feature not seen in other SCAs. A large family with autosomal dominant myoclonic-dystonia was also mapped to a missense mutation in the D2 dopamine receptor gene (S54.001). These loci will undoubtedly be available for commercial genetic testing within the next year or two.
Many advances in treating Parkinson’s disease (PD) have been made in the last several years. Joseph Friedman (P003.065) reported his experience with quetiapine (Seraquel), a new atypical neuroleptic used for treating levodopa-induced psychosis in PD patients. Patients had excellent control of psychosis at 40.6 mg per day of the drug, without worsening of their motor performance. Unlike clozapine (Clozaril), this agent does not require weekly blood monitoring, leading many patients to switch successfully from Clozaril to Seraquel. Viagra (sildenafil) was evaluated in 10 PD patients with erectile dysfunction (P03.067) and was found to be effective and safe. The Parkinson Study Group reported placebo-controlled clinical trials of the glutamate antagonist remacemide in levodopa-treated Parkinson patients (S34.003). The drug improved motor performance and "on" time, but did not improve levodopa-induced dyskinesias. Several presentations discussed the new non-ergot dopamine agonist pramipexole (Mirapex). Long-term safety and efficacy data from open label studies in several hundred early (S34.001) and late (S34.002) Parkinson patients demonstrated that Mirapex was efficacious, safe, and well tolerated. Frucht and colleagues (P05.036), however, reported eight functionally independent Parkinson patients who experienced sudden sleep attacks on Mirapex, resulting in auto accidents, a serious side effect.
As summarized in the December Neurology Alert (Frucht S. Neurol Alert 1998;17:26-27), Grenoble neurologists reported benefits in motor performance and functional status in PD lasting up to four years after implanting and stimulating the bilateral subthalamic nucleus (STN) S38:VO2. (The procedure is not presently approved in the United States.) Their study (S38.003) established preoperative indicators of clinical outcome from stimulating STN. Younger patients responded better, and major parkinsonian symptoms (akinesia, tremor, rigidity, gait, and postural stability) that respond to levodopa also improved with STN stimulation. Cognitive performance, as well as mood and executive function, may actually improve after surgery (P06.091). In a small series of patients, Hammerstad reported that bilateral internal globus pallidus stimulation (S38.001) was nearly as effective as bilateral STN stimulation. However, patients with pallidal stimulators continued to take levodopa, while STN stimulator patients were able to significantly reduce their levodopa dose.
Vim thalamic stimulation to treat unilateral tremor of PD and essential tremor is currently approved in the United States. Pahwa showed that thalamic stimulation of patients with essential tremor (S62.004) was as effective in relieving tremor as thalamotomy, with fewer complications.
The most eagerly anticipated report was the NIH-sponsored, double-blind, controlled trial of human cell transplants in advanced PD (S38.005, P05.026, P05.027, P05.028). Embryonic mesencephalic transplants were performed in double-blinded fashion on 40 patients with advanced disease. Half of the patients were older than age 60 in order to evaluate the variable of host age. Embryonic mesencephalon tissue, taken 7-8 weeks postconception from elective abortions, was implanted bilaterally into the putamen. Patients were followed with fluorodopa PET scanning and multiple clinical measures. After one year, the blind was broken and subjects who received placebo surgery (placement of burr holes without needle passage into the brain) were offered fetal transplantation. Briefly summarized, PET analysis demonstrated graft survival and improvement in fluorodopa PET transmission, but the changes failed to produce clinical benefit in patients older than 60 years. Also, several patients showing increased PET activity developed intractable face and arm dyskinesias despite discontinuing levodopa, a consequence that seriously reduces the practical application of the technique. Paradoxically, several placebo patients reported measurable parkinsonian improvement at one year. —sf (Steven Frucht, MD, is Assistant Professor of Neurology, Movement Disorders Division, Columbia-Presbyterian Medical Center.)
A serious side effect for some Parkinson patients taking the drug pramipexole (Mirapex) is:
a. severe headaches.
b. seizures.
c. sudden sleep attacks.
d. nausea.
Embryonic mesencephalic transplants failed to produce clinical benefit in patients:
a. younger than 60 years of age.
b. older than 60 years of age.
c. 50-60 years of age.
d. 60-70 years of age.
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